Dredging of a highly contaminated canal along the shore of Lake Michigan has begun, triggering fears among some experts that the project could release harmful chemicals into an Indiana community.

To dig a deeper canal for ships, the U.S. Army Corps of Engineers is removing large volumes of contaminated sediment – equivalent to about 160 million truckloads – from the Indiana Harbor and Canal.

The canal already contributes a significant amount of polychlorinated biphenyls (PCBs) to East Chicago’s air. And that load of pollution could skyrocket as the Corps dredges into deep sediment, said Keri Hornbuckle, a professor at the University of Iowa’s department of civil and environmental engineering.

“I’m not as worried about the dredging process itself, but what they could leave behind on the surface,” Hornbuckle said. “That’s the stuff that will get into the air.”

A new, as-yet unpublished study has found that indoor air in East Chicago, a low-income area inhabited almost entirely by Hispanics and African Americans, already has PCB levels about three times higher than its outdoor air.

For five decades, beginning in the 1930s, a now-defunct refinery discharged the chemicals, which were banned in the late 1970s, into the canal. Widely used as electrical insulators and industrial lubricants, PCBs have been linked to many health effects, including cancer, reduced IQs in children and asthma.

The canal’s sediment is “among the most contaminated and toxic” ever reported, according to a 2002 U.S. Geological Survey study.

Connecting the Grand Calumet River to Lake Michigan, the Indiana Harbor and Canal is designated an “Area of Concern,” a term used by the U.S. Environmental Protection Agency for environmentally degraded sites in the Great Lakes basin.

In a $180-million project that will take eight to 10 years, the Army Corps will be removing 1.6 billion cubic yards of sediment from several feet below the surface, where PCB concentrations are up to six times higher than surface sediments, according to a 2011 study led by Hornbuckle.

“If the underlying sediment is twice as concentrated with PCBs as the surface sediment they’re getting rid of, then it’s likely the airborne levels will double” in East Chicago, Hornbuckle said.

Jennifer Miller, an Army Corps environmental engineer based in Chicago, said the Corps is continuously monitoring the air for petroleum-based compounds. In addition, air samples checking for PCBs and metals near the disposal site and dredging areas are collected every six days, and the results will be available a couple of months after that, she said.

Miller said there are “multiple viewpoints on whether a compound is considered non-volatile or volatile” and that high levels of PCBs and metals won’t be released into the community’s air.

But Hornbuckle said PCBs are readily transformed into a gas. The canal already emits about 15 pounds of PCBs into the air every year, according to Hornbuckle’s 2011 study.

Ron Hites, a professor at Indiana University’s School of Public and Environmental Affairs who specializes in air monitoring in the Great Lakes basin, agreed with Hornbuckle, saying PCBs on surface waters become airborne.

People are usually exposed through eating tainted fish, but PCBs can be inhaled, too.

The potential for additional PCBs from the dredging could add to a heavy pollution burden already faced by East Chicago’s 29,764 residents, who are 92 percent Hispanic and African American, according to U.S. Census data. Thirty-six percent of its households have incomes under the poverty level, more than three times higher than Indiana’s poverty rate. The region, Lake County, has the state’s highest hospitalization rate for asthma, according to the Indiana Department of Community Health.

There are no local studies linking the contamination to health problems but the canal has long symbolized the region’s industrial history and legacy contamination.

Most people in East Chicago “have never known an environment that wasn’t severely degraded,” said Alex da Silva, a professor and director of science programs at Calumet College who worked with the East Chicago community leading up to the dredging.

The harbor is one of the busiest in the Great Lakes, with 10 to 15 million tons of iron ore, limestone, coke, gypsum, steel, cement, petroleum and other products passing through there each year, generating about $894 million annually. The Army Corps estimates that harbor activity supports about 3,665 jobs.

“The economic reality is that the people who live there are not going to benefit economically from this,” Hornbuckle said. “The big corporations need the barges and they’re the ones benefiting. The people who live there are the people taking the health risk and they don’t have much voice.”

Local officials, however, disagree, saying the project will improve East Chicago’s environment.

“The dredging project will certainly improve our local economy and help clean our waterways,” Fernando Trevino, executive director of the East Chicago Waterway Management District, which owns the landfill, said in a prepared statement.

Indiana Department of Environmental Management Commissioner Thomas Easterly called it “an important step towards remediation and restoration efforts to improve water quality."

The project is designed mostly for improving navigation in the canal. But Army Corps project manager Mike Nguyen said there will be environmental benefits from reducing the 88 pounds of PCBs that the canal sends into Lake Michigan every year.

Da Silva agreed. “Many people in this region are not just fishing for fun, they’re in the river and canal trying to catch fish to eat -- regardless of advisories,” he said.

Joel Brammeier, president of the Alliance for the Great Lakes, said his organization “absolutely supports dredging to get rid of these contaminants” but remains concerned over the disposal.

The removed sediment will be taken to a newly built landfill nearby. The landfill, where the former refinery was, sits within 800 yards of East Chicago Central High School.

Miller said there will be long-term air monitoring at the high school. The EPA conducted a health study in 2006 for the landfill and found “relatively low health risks to nearby residents.”

The entire Chicago metro area (East Chicago is about 25 miles southeast of Chicago) has elevated levels of PCBs and other contaminants, Hites said.

“PCB levels in cities like Chicago and Cleveland are sometimes as much as 30 times higher” than non-urban sites in the Great Lakes basin, said Hites, whose 2011 study showed air in the Chicago area has some of the most elevated PCB levels of American cities.

Sources weren’t identified, but Hites speculates the elevated levels reflect past use in the industrial region.

The East Chicago problem “is a good example of why it’s important to not put these (contaminants) in the lakes in the first place,” Brammeier said.

This article originally ran at Environmental Health News, a news source published by Environmental Health Sciences, a nonprofit media company.